scholarly journals Ubiquitous Molecular Outflows in z > 4 Massive, Dusty Galaxies. II. Momentum-driven Winds Powered by Star Formation in the Early Universe

2020 ◽  
Vol 905 (2) ◽  
pp. 86 ◽  
Author(s):  
Justin S. Spilker ◽  
Manuel Aravena ◽  
Kedar A. Phadke ◽  
Matthieu Béthermin ◽  
Scott C. Chapman ◽  
...  
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
Molecular Outflows ◽  
Dusty Galaxies

Tracing young SMBHs in the dusty distant universe – a Chandra view of DOGs

2020 ◽  
Vol 15 (S359) ◽  
pp. 17-21
Author(s):  
Karín Menéndez-Delmestre ◽  
Laurie Riguccini ◽  
Ezequiel Treister
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Far Infrared ◽  
Host Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Near Ir ◽  
X Ray Imaging ◽  
Combined Use ◽  
Dusty Galaxies

AbstractThe coexistence of star formation and AGN activity has geared much attention to dusty galaxies at high redshifts, in the interest of understanding the origin of the Magorrian relation observed locally, where the mass of the stellar bulk in a galaxy appears to be tied to the mass of the underlying supermassive black hole. We exploit the combined use of far-infrared (IR) Herschel data and deep Chandra ˜160 ksec depth X-ray imaging of the COSMOS field to probe for AGN signatures in a large sample of >100 Dust-Obscured Galaxies (DOGs). Only a handful (˜20%) present individual X-ray detections pointing to the presence of significant AGN activity, while X-ray stacking analysis on the X-ray undetected DOGs points to a mix between AGN activity and star formation. Together, they are typically found on the main sequence of star-forming galaxies or below it, suggesting that they are either still undergoing significant build up of the stellar bulk or have started quenching. We find only ˜30% (6) Compton-thick AGN candidates (NH > 1024 cm–2), which is the same frequency found within other soft- and hard-X-ray selected AGN populations. This suggests that the large column densities responsible for the obscuration in Compton-thick AGNs must be nuclear and have little to do with the dust obscuration of the host galaxy. We find that DOGs identified to have an AGN share similar near-IR and mid-to-far-IR colors, independently of whether they are individually detected or not in the X-ray. The main difference between the X-ray detected and the X-ray undetected populations appears to be in their redshift distributions, with the X-ray undetected ones being typically found at larger distances. This strongly underlines the critical need for multiwavelength studies in order to obtain a more complete census of the obscured AGN population out to higher redshifts. For more details, we refer the reader to Riguccini et al. (2019).

scholarly journals Clumpy Galaxies in the Early Universe

2006 ◽  
Vol 2 (S235) ◽  
pp. 376-380 ◽  
Author(s):  
Debra Meloy Elmegreen
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
Spiral Galaxies ◽  
Star Forming ◽  
Wide Range ◽  
Thick Disks ◽  
Hubble Ultra Deep Field

AbstractClumpy galaxies are prominent in the early Universe. We present morphological and photometric properties of a wide range of galaxy types and their star-forming clumps in the Hubble Ultra Deep Field. Sizes, scale lengths, and scale heights suggest that galaxies grow by a factor of 2 fromz= 4 to the present, and that thick disks are present in the early Universe. The largest clumps of star formation are 107–109M⊙in different galaxies, much more massive than large star-forming complexes in local galaxies. Dissolved clumps may account for both the exponential disks and the early thick disks of spirals and proto-spiral galaxies.

scholarly journals Radiative Feedback Effects during Cosmic Reionization

2014 ◽  
Vol 11 (S308) ◽  
pp. 372-377
Author(s):  
David Sullivan ◽  
Ilian T. Iliev
Keyword(s):  
Star Formation ◽  
Radiation Field ◽  
Early Universe ◽  
Galaxy Formation ◽  
Analytical Models ◽  
Feedback Effects ◽  
Radiative Feedback ◽  
Hydrodynamical Simulations ◽  
Matching Models ◽  
The Impact

AbstractWe present coupled radiation hydrodynamical simulations of the epoch of reionization, aimed at probing self-feedback on galactic scales. Unlike previous works, which assume a (quasi) homogeneous UV background, we self-consistently evolve both the radiation field and the gas to model the impact of previously unresolved processes such as spectral hardening and self-shielding. We find that the characteristic halo mass with a gas fraction half the cosmic mean, Mc(z), a quantity frequently used in semi-analytical models of galaxy formation, is significantly larger than previously assumed. While this results in an increased suppression of star formation in the early Universe, our results are consistent with the extrapolated stellar abundance matching models from Moster et al. 2013.

scholarly journals The Galactic Center compared with nuclei of nearby galaxies

2016 ◽  
Vol 11 (S322) ◽  
pp. 245-252 ◽  
Author(s):  
Francoise Combes
Keyword(s):  
Star Formation ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Molecular Outflows ◽  
Star Formation Activity ◽  
Nearby Galaxies

AbstractUnderstanding our Galactic Center is easier with insights from nearby galactic nuclei. Both the star formation activity in nuclear gas disks, driven by bars and nuclear bars, and the fueling of low-luminosity AGN, followed by feedback of jets, driving molecular outflows, were certainly present in our Galactic Center, which appears now quenched. Comparisons and diagnostics are reviewed, in particular of m = 2 and m = 1 modes, lopsidedness, different disk orientations, and fossil evidences of activity and feedback.

scholarly journals Molecules in star formation

1997 ◽  
Vol 178 ◽  
pp. 19-30 ◽  
Author(s):  
F.H. Shu
Keyword(s):  
Star Formation ◽  
Molecular Diagnostics ◽  
Accretion Disks ◽  
Central Star ◽  
Flow Dynamics ◽  
Molecular Outflows ◽  
Self Similar ◽  
Cloud Cores ◽  
Cloud Core ◽  
Review Current

We review current ideas and models in the problem of star formation from molecular cloud cores that are relatively isolated from the influences of other forming stars. We discuss the time scales, flow dynamics, and density and temperature structures applicable to each of the four stages of the entire process: (a) formation of a magnetized cloud core by ambipolar diffusion and evolution to a pivotal state of gravomagneto catastrophe; (b) self-similar collapse of the pivotal configuration and the formation of protostars, disks, and pseudo-disks; (c) onset of a magnetocentrifugally driven, lightly ionized wind from the interaction of an accretion disk and the magnetosphere of the central star, and the driving of bipolar molecular outflows; (d) evolution of pre-main-sequnce stars surrounded by dusty accretion disks. For each of these stages and processes, we consider the characteristics of the molecular diagnostics needed to investigate the crucial aspects of the observational problem.

scholarly journals Cluster Mass and Metallicity Distributions: Reconstructing the Events During Halo Formation

2002 ◽  
Vol 207 ◽  
pp. 545-554
Author(s):  
William E. Harris
Keyword(s):  
Star Formation ◽  
Mass Distribution ◽  
Early Universe ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Potential Wells ◽  
Cluster Mass ◽  
Galactic Potential ◽  
Initial Power ◽  
Lines Of Evidence

Globular clusters in most large galaxies are a mixture of metal-poor and metal-rich (bimodal), but the halo stars are almost entirely metal-rich. This and other lines of evidence argue that the metal-poor globular clusters formed within widely distributed 108 − 109M⊙ gas clouds (supergiant GMCs) during an early burst in which most of the gas was ejected or unused till later rounds of star formation.New simulations of the growth of pre-galactic potential wells in the early universe now indicate that the initial power-law form of the globular cluster mass distribution (dN/dM ∼ M-1.8) is a miniature replica of the mass distribution of the SGMCs themselves, which grow hierarchically in the CDM potential wells of large protogalaxies.

scholarly journals Supernova dust formation and the grain growth in the early universe: the critical metallicity for low-mass star formation

2014 ◽  
Vol 446 (3) ◽  
pp. 2659-2672 ◽  
Author(s):  
Gen Chiaki ◽  
Stefania Marassi ◽  
Takaya Nozawa ◽  
Naoki Yoshida ◽  
Raffaella Schneider ◽  
...  
Keyword(s):  
Star Formation ◽  
Grain Growth ◽  
Early Universe ◽  
Dust Formation ◽  
Mass Star ◽  
Low Mass

scholarly journals Discovery of new bright ULIRGs from the IRAS PSC/FSC Combined Catalogue

2018 ◽  
Vol 2 (1) ◽  
pp. 13-20
Author(s):  
G. A. Mikayelyan ◽  
◽  
A. M. Mickaelian ◽  
H. V. Abrahamyan ◽  
G. M. Paronyan ◽  
...  
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
Formation Processes ◽  
Direct Impact ◽  
High Luminosity ◽  
Nuclear Activity ◽  
Active Star ◽  
Multiple Structure ◽  
Activity Types ◽  
Very High

High-luminosity IR galaxies (LIRGs, ULIRGs, and HLIRGs) are important for studies related to star-formation processes in the early Universe, as their luminosity allows to detect them at large distances. High IR indicates active star-formation and often starburst processes, which is typical to HII (starburst, SB) and AGN. An interesting question is whether the starburst triggers AGN or vice versa or there is no direct impact. Considering that very often such objects manifest double and multiple structure, it is also interesting to investigate the interrelationship between the SB, nuclear activity and interactions or merging. We have analyzed the IRAS PSC/FSC Combined Catalogue for search for new bright ULIRGs. By means of the SDSS DR14 data, namely redshifts for those objects having spectroscopy, we have calculated the IR luminosities and have found 114 very high-luminosity IR galaxies; 107 ULIRGs and 7 HLIRGs. Among them, 48 new ULIRGs and 7 new HLIRGs have been discovered. These objects have been studied by SDSS color-color, luminosity-redshift and other diagrams. Further studies will include the content of the sample for activity types and other available data.

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